docs: def from_json(cls, json_text):
          """
          Returns a UnitRegistry object from a json-serialized unit registry
  
          Parameters
          ----------
  
          json_text : str
             A string containing a json represention of a UnitRegistry
          """
          data = json.loads(json_text)
          lut = {}
          for k, v in data.items():
              unsan_v = list(v)
              unsan_v[1] = sympify(v[1], locals=vars(unyt_dims))
              lut[k] = tuple(unsan_v)
  
          return cls(lut=lut, add_default_symbols=False)